<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta http-equiv="X-UA-Compatible" content="ie=edge" />
    <title>Document</title>
    <style>
      * {
        margin: 0;
        padding: 0;
      }

      img {
        width: 100%;
        height: 100%;
        display: block;
      }

      .box {
        width: 450px;

        margin: 50px;
        display: flex;
        flex-direction: column;

        position: relative;
      }

      .box > .show {
        width: 450px;
        height: 450px;
        border: 1px solid #333;
        position: relative;
      }

      .box > .show > .mask {
        width: 200px;
        height: 200px;
        background-color: yellow;
        opacity: 0.4;
        position: absolute;
        top: 0px;
        left: 0px;

        display: none;
      }

      .box > .list {
        width: 100%;
        flex: 1;

        display: flex;
        justify-content: flex-start;
        align-items: center;

        box-sizing: border-box;
        padding: 20px;
      }

      .box > .list > p {
        width: 54px;
        height: 54px;
        border: 1px solid #333;
        margin-right: 10px;
      }

      .box > .list > p.active {
        border-color: red;
      }

      .box > .enlarge {
        width: 400px;
        height: 400px;

        position: absolute;
        top: 0;
        left: 101%;

        background: url(../images/1.big.jpg) no-repeat;
        background-size: 800px 800px;
        background-position: 0 0;

        display: none;
      }
    </style>
  </head>
  <body>
    <div class="box">
      <div class="show">
        <img src="../images/1.jpg" alt="" />
        <div class="mask"></div>
      </div>
      <div class="list">
        <p class="active">
          <img
            src="../images/1.small.jpg"
            showImg="../images/1.jpg"
            enlargeImg="../images/1.big.jpg"
            alt=""
          />
        </p>
        <p>
          <img
            src="../images/2.small.jpg"
            showImg="../images/2.jpg"
            enlargeImg="../images/2.big.jpg"
            alt=""
          />
        </p>
      </div>
      <div class="enlarge"></div>
    </div>
    <script src="../js/lenlarg.js"></script>
  </body>
</html>
